Weft yarn control apparatus

ABSTRACT

Weft yarn control apparatus for use in a weaving loom and having a signal generator arranged in a shuttle to generate a signal of a given resonance during normal running of the yarn, and to generate a signal of a second resonance upon yarn breakage, the signals being transferred to a receiver inductively coupled with the generator and which, upon receipt of a breakage signal, produces an impulse effective to immobilize the loom.

United States Patent 2,535,36912/1950 Pelce Inventors Peter Dosch Jona;

Reinhard Heck, Wattwil; Ernst Hubeli, Wattwil, all of Switzerland May15, 1969 Oct. 19, 1971 Heberlein & Co. AG.

Wattwil, Canton of St. Gall, Switzerland May 17, 1968 Switzerland Appl.No. Filed Patented Assignee Priority WEFI YARN CONTROL APPARATUS 7Claims, 4 Drawing Figs.

U.S. Cl 139/371 Int. Cl ....D03d 51/34 Field 0fSearch..... 139/371, 370,336

References Cited UNITED STATES PATENTS 3,298,401 Stutz l39/371 3,322,l625/1967 Rydbom... 139/371 3,467,]49 9/1969 Dosch et al... l39/37l3,485,964 12/1969 Stutz etal. 139/371 X FOREIGN PATENTS 1,473,899 2/1967France 139/371 918,529 2/1963 Great Britain... 139/371 455,672 7/1968Switzerland 139/336 1,253,647 11/1967 Germany 139/371 PrimaryExaminer-James Kee Chi Attorney-Ward, McElhannon, Brooks & FitzpatrickABSTRACT: Weft yarn control apparatus for use in a weaving loom andhaving a signal generator arranged in a shuttle to generate a signal ofa given resonance during normal running of the yarn, and to generate asignal of a second resonance upon yarn breakage, the signals beingtransferred to a receiver inductively coupled with the generator andwhich, upon receipt of a breakage signal, produces an impulse effectiveto immobilize the loom.

PATENTEfinm 19 197i 3.613.744 SHEETlUF 2 v i .1- Ti 32 INVENTORS l am/eme,

WEFT YARN CONTROL APPARATUS This invention relates to apparatus for thecontrol of weft yarns, and more particularly for monitoring the entry ofweft yarn in weaving looms and to effect immediate immobilization of theloom upon breakage of the weft yarn.

I-Ieretofore, a number of devices have been applied to weaving looms orto shuttles therefor for the purpose of shutting down the loom uponbreakage of the weft yarn. However, to applicants knowledge, no suchdevices have been entirely satisfactory, usually because of theircomplexity or because their response time has not been sufficientlyrapid to shut down the loom prior to the laying-in of one or more picksafter the yarn breakage occurs.

We have conceived by our invention a control apparatus of the classdescribed by which we are able to overcome the foregoing difficultiesand disadvantages. Thus, we contribute apparatus according to which asignal generator arranged in the shuttle is adapted to transfer a signalto a receiver fixed on the weaving slay and indicating according to itsresonance frequency whether the yarn is running normally or whether abreakage has occurred or the yarn end has been drawn off the weft coil.Only relatively few parts are needed in our apparatus, and these arereadily able to withstand the rough treatment nonnally received by ashuttle. Additionally, a breakage signal can be used immediately to shutdown the loom.

According to the present inventive concept, we contribute weft yarncontrol apparatus for a weaving loom, comprising: a signal generatormounted in a shuttle and adapted to transmit a signal of a givenresonance during proper running of the weft yarn, and a signal of asecond reference upon relaxation of the yarn due to breakage or thelike, and a receiver inductively coupled with the signal generatorwhich, upon receipt of the second signal produces a control impulsewhich immobilizes the loom.

As a feature of our invention, the generator may include an oscillatingcircuit having a tuning coil and an armature mounted for movementrelatively to the coil responsive to tension in the weft yarn; and meansare cooperatively arranged in respect of the armature to shift same uponrelaxation of the yarn tension. A condenser may be connected in parallelwith the tuning coil and with a coupling coil to obtain a variation inresonance frequency of the oscillation circuit upon movement of thearmature relatively to the tuning coil.

The armature may be formed of a ferromagnetic material and may becarried by a lever pivotally mounted to move the armature towards thetuning coil when the yarn is brought under normal running tension andaway from the tuning coil when the tension is relaxed. Actually, weprefer to use magnet means for exerting a force upon the lever to urgethe same, and the armature mounted thereon, away from the tuning coil;and in this connection, a pair of suitably oriented magnets may be used,one mounted on the lever itself, and the other conveniently mountednearby.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent construction as do not depart from the spiritand scope of the invention.

A specific embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a vertical sectional view illustrating an illustrativeembodiment of our invention, and showing the armature under a no-tensionposition in solid lines, and in active position in broken lines;

FIG. 2 is a view similar to that of FIG. I but illustrating amodification thereof;

FIG. 3 is also a vertical sectional view of apparatus according to thepresent invention, but illustrating still a further modificationthereof; and

FIG. 4 is a cross-sectional view illustrating an arrangement of magnetsfor exerting a retractive force in respect of the armature.

Referring now to the drawings, and more particularly to FIG. 1 thereof,there is shown a housing 1 which may be positioned in the throat of ashuttle near the yarn supply, and which is formed with a yarn lead-ingroove 2 for receiving a weft yarn 3. A lever 4 is mounted at 5 forpivotal movement within the housing 1 and is shown in its inactiveposition in solid lines and in its active position in broken lines, asindicated at 4'. It will be noted that the length of the lever 4 passesacross the lead-in groove 2.

A magnet 8 is mounted in the lever 4 opposite a cooperating magnet 7fixed in the wall of the housing 1, these magnets combining to exert aforce on the lever 4 tending to pivot the same to the position indicatedin solid lines; and when the tension in the yarn 3 is sufficientlyrelaxed, the lever 4 will assume that position. However, when the loomis operating and the tension in the yarn 3 is normal for operatingconditions, the yarn will force the lever 4 downwardly into the positionindicated at 4', in which position, a ferromagnetic armature 6 fixed atthe end of the lever 4 is brought into proximity to an inductive tuningcoil 9 conveniently positioned in the wall 23 of the housing 1.

The magnetic armature 6 may also consist of electrically conductivematerial preferably a nonferrous metallic material such as aluminumwhereby to influence the resistance loss in the tuning coil 9.

The tuning coil 9, together with a coupling coil 11 arranged at thebottom l0 of the housing 1, and a condenser 12 connected in parallelwith the two coils, forms a resonance circuit 29.

From the description thus far, it will be appreciated that movement ofthe lever 4 about its pivot point 5 will shift the armature 6 towards oraway from the tuning coil 9, dependent upon the tension in the yarn 3,thus to vary the resonance in the oscillation circuit; and that at acertain frequency, a control impulse may be transmitted for the purposeof immobilizing the loom.

Turning now to the modification of FIG. 2, the tuning coil 13 andretraction magnet 14 are arranged in the upper part of the housing 1 andabove the lever 15 which, in this case, pivots about a pointconveniently located at its right hand side, as viewed. In the inactiveposition, armature I6 mounted 0 on the lever 15 is brought toward thetuning coil 13; while in active position, it is moved away from the coil13. Thus, the resonance frequency of the oscillation circuit 30 whichincludes the tuning coil 13, the condenser 36 and the coupling coil 37positioned at the bottom of the housing I, is varied. Again, the lever15 is urged towards its active position by the tension in the yarn 3,and when that tension is relaxed, is brought into its inactive positionby the action of the magnets 14 and 17, the latter being mounted in thelever 15.

A further modification of the invention is illustrated in FIG. 3,according to which the magnet 14, the lever 15, and the magnet 28mounted in the lever are arranged generally along the lines of theembodiment of FIG. 2. The inductance of the resonant circuit 31,consisting of the condenser 34 and coil 18 is, however, influenced bythe position of the lever 15 which, when pivoted downwardly as viewed,brings the ferromagnetic armature 27 into the inner field 19 of the coil18. It will be appreciated, therefore, that movement of the lever 15relatively to the coil 18 will vary the resonance in the latter coil. Inthis case, the coil 18 is wound so as to serve as a tuning coil as wellas a coupling coil.

FIG. 4 illustrates a multimagnet system acting as the retraction forcefor the lever 20. in this embodiment, a magnet 22 is positioned at oneend of the lever while a second magnet 24 is mounted in the sidewall 23of the housing 1, and a further magnet 26 is mounted in the upper wall25 of the housing. The magnets 22 and 24 are so oriented that theiropposite poles are adjacent one another when the lever is in theposition illustrated in solid lines, thus to effect an attractive force.This movement is enhanced by the magnet 26 which is so oriented inrespect of the magnet 22 as to repel the lever 20 towards the positionillustrated in solid lines, thereby creating a somewhat larger force ofretraction to bring the lever into the inactive position than that forcewhich is effected by the magnets 22 and 24 alone.

Again, it will be appreciated that the impulse created by movement ofthe armature mounted in the lever to the inactive position can beapplied by known means to efiect immediate immobilization of the weavingloom so that the same is brought to a stop as soon as a defect signal isreceived.

We believe that the construction and operation of our novel weft yarncontrol apparatus will now be understood, and the advantages of ourinvention will be fully appreciated by those persons skilled in the art.

We claim:

1. Apparatus for producing a detectable electrical signal which may beused in immobilizing a loom upon breakage of the weft yarn whichcomprises:

a weft yarn shuttle;

a resonant electrical circuit mounted in said shuttle, said circuitincluding a tuning element;

an armature mounted in said shuttle for movement relative to said tuningelement for influencing its tuning effect on said resonant circuitwhereby the position of said armature relative to said tuning elementchanges the resonant frequency of said circuit; and

means for guiding a weft yarn in said shuttle across the path ofarmature movement to hold said armature in difierent positions relativeto said tuning element according to the tension in said weft yarn.

2. Apparatus according to claim 1 wherein said tuning element is atuning coil and said resonant electrical circuit further includescondenser means connected with said tuning coil and a coupling coil toobtain a variation in resonance frequently of said circuit upon movementof said an-nature relatively to said tuning coil.

3. Apparatus according to claim 1, wherein said armature is carried by alever pivotably mounted to move said armature towards said tuningelement when said yarn is brought under normal running tension and awayfrom said element when said tension is relaxed.

4. Apparatus according to claim 3, wherein said armature consists ofelectrically conductive material.

5. Apparatus according to claim 3 wherein said armature is aferromagnetic material.

6. Apparatus according to claim 3 further including magnet means toshift said lever relatively to said tuning element upon relaxation oftension in the yarn.

7. Apparatus according to claim 6, wherein said magnet means comprise afirst magnet mounted on said lever and a second magnet cooperativelyoriented relatively to said first magnet to exert a force on said leverto urge said armature away from said tuning coil.

1. Apparatus for producing a detectable electrical signal which may beused in immobilizing a loom upon breakage of the weft yarn whichcomprises: a weft yarn shuttle; a resonant electrical circuit mounted insaid shuttle, said circuit including a tuning element; an armaturemounted in said shuttle for movement relative to said tuning element forinfluencing its tuning effect on said resonant circuit whereby theposition of said armature relative to said tuning element changes theresonant frequency of said circuit; and means for guiding a weft yarn insaid shuttle across the path of armature movement to hold said armaturein different positions relative to said tuning element according to thetension in said weft yarn.
 2. Apparatus according to claim 1 whereinsaid tuning element is a tuning coil and said resonant electricalcircuit further includes condenser means connected with said tuning coiland a coupling coil to obtain a variation in resonance frequently ofsaid circuit upon movement of said armature relatively to said tuningcoil.
 3. Apparatus according to claim 1, wherein said armature iscarried by a lever pivotably mounted to move said armature towards saidtuning element when said yarn is brought under normal running tensionand away from said element when said tensiOn is relaxed.
 4. Apparatusaccording to claim 3, wherein said armature consists of electricallyconductive material.
 5. Apparatus according to claim 3 wherein saidarmature is a ferromagnetic material.
 6. Apparatus according to claim 3further including magnet means to shift said lever relatively to saidtuning element upon relaxation of tension in the yarn.
 7. Apparatusaccording to claim 6, wherein said magnet means comprise a first magnetmounted on said lever and a second magnet cooperatively orientedrelatively to said first magnet to exert a force on said lever to urgesaid armature away from said tuning coil.